- Spring Boot – API Docs with springdoc-openapi
Springfox is dead; springdoc is what generates OpenAPI 3 from your controllers now. Wiring it up, documenting an endpoint properly, describing JWT auth so the Try It Out button works — and the version pin Boot 4 forces on you, because Boot no longer manages springdoc's version.
- TypeScript – Get Started
Start here. What TypeScript actually is — a type checker that erases itself, not a language that runs — the three kinds of bug it catches and the one class it cannot, the exact versions this track is written against, the pizza ordering app every example is taken from, and the full lesson index in reading order.
- Python – String Methods
The string methods worth memorising — strip, split, join, replace, startswith, and the case pair — plus slicing, why strings are immutable, and why building one in a loop with `+=` is the wrong tool.
- Functional Interfaces
A functional interface is an interface with exactly one abstract method. That single rule is what makes lambdas work: when the compiler sees a lambda, it needs to know which method the lambda is implementing, and one abstract method means there is no ambiguity. The rule, and the annotation…
- React – Updating State Correctly
Setting state does not change the variable you are holding — it schedules a render with a new one. State as a snapshot, why two increments in a row only count once, the updater function that fixes it, and updating objects and arrays without mutating them so React can still tell that something changed.